Substractive Resource

Li-Ta Lo <ollie at lanl.gov> writes:
> Eric,
>> You explained substractive decoding to me long time ago but I really
> forgot what it is. Could you tell me again ? Hoe do you determine if
> some resource of some device is substractive ? Form the data sheet ?
A subtractive bridge resource is a bridge resource that picks
up the unclaimed transactions and forwards them on. In networking
the equivalent concept the default route. A subtractive resource
is what picks up all of the traffic on a bus that does not have a
specific route to somewhere else.
Eric